On Thu, Sep 14, 2023 at 05:05:17PM +0300, Arseniy Krasnov wrote:
Hello Stefano,
On 14.09.2023 17:07, Stefano Garzarella wrote:
Hi Arseniy,
On Mon, Sep 11, 2023 at 11:22:30PM +0300, Arseniy Krasnov wrote:
Hello,
this patchset is first of three parts of another big patchset for
MSG_ZEROCOPY flag support:
https://lore.kernel.org/netdev/20230701063947.3422088-1-AVKrasnov@xxxxxxxxxxxxxx/
During review of this series, Stefano Garzarella <sgarzare@xxxxxxxxxx>
suggested to split it for three parts to simplify review and merging:
1) virtio and vhost updates (for fragged skbs) <--- this patchset
2) AF_VSOCK updates (allows to enable MSG_ZEROCOPY mode and read
tx completions) and update for Documentation/.
3) Updates for tests and utils.
This series enables handling of fragged skbs in virtio and vhost parts.
Newly logic won't be triggered, because SO_ZEROCOPY options is still
impossible to enable at this moment (next bunch of patches from big
set above will enable it).
I've included changelog to some patches anyway, because there were some
comments during review of last big patchset from the link above.
Thanks, I left some comments on patch 4, the others LGTM.
Sorry to not having spotted them before, but moving
virtio_transport_alloc_skb() around the file, made the patch a little
confusing and difficult to review.
Sure, no problem, I'll fix them! Thanks for review.
In addition, I started having failures of test 14 (server: host,
client: guest), so I looked better to see if there was anything wrong,
but it fails me even without this series applied.
It happens to me intermittently (~30%), does it happen to you?
Can you take a look at it?
Yes! sometime ago I also started to get fails of this test, not ~30%,
significantly rare, but it depends on environment I guess, anyway I'm going to
look at this on the next few days
Maybe it's just a timing issue in the test, indeed we are expecting 8
bytes but we received only 3 plus the 2 bytes we received before it
seems exactly the same bytes we send with the first
`send(fd, HELLO_STR, strlen(HELLO_STR), 0);`
Since it is a stream socket, it could happen, so we should retry
the recv() or just use MSG_WAITALL.
Applying the following patch fixed the issue for me (15 mins without
errors for now):
diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index 90718c2fd4ea..7b0fed9fc58d 100644
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -1129,7 +1129,7 @@ static void test_stream_virtio_skb_merge_server(const struct test_opts *opts)
control_expectln("SEND0");
/* Read skbuff partially. */
- res = recv(fd, buf, 2, 0);
+ res = recv(fd, buf, 2, MSG_WAITALL);
if (res != 2) {
fprintf(stderr, "expected recv(2) returns 2 bytes, got %zi\n", res);
exit(EXIT_FAILURE);
@@ -1138,7 +1138,7 @@ static void test_stream_virtio_skb_merge_server(const struct test_opts *opts)
control_writeln("REPLY0");
control_expectln("SEND1");
- res = recv(fd, buf + 2, sizeof(buf) - 2, 0);
+ res = recv(fd, buf + 2, 8, MSG_WAITALL);
if (res != 8) {
fprintf(stderr, "expected recv(2) returns 8 bytes, got %zi\n", res);
exit(EXIT_FAILURE);
I will check better all the cases and send a patch upstream.
Anyway it looks just an issue in our test suite :-)
Stefano
Thanks, Arseniy
host$ ./vsock_test --mode=server --control-port=12345 --peer-cid=4
...
14 - SOCK_STREAM virtio skb merge...expected recv(2) returns 8 bytes, got 3
guest$ ./vsock_test --mode=client --control-host=192.168.133.2 --control-port=12345 --peer-cid=2
Thanks,
Stefano
